1. Field of the Invention
The present invention relates to a two-axis hinge device suitable for use in a mobile phone, a personal handyphone system (PHS), a personal digital assistant (PDA), a portable game device, a notebook personal computer, etc., which includes a first housing and a second housing that are connected to each other with a hinge unit, and to a mobile terminal apparatus.
More particularly, the present invention relates to a two-axis hinge device which includes a first-rotation-axis defining unit and a second-rotation-axis defining unit that are perpendicular to each other. The second-rotation-axis defining unit has a substantially cylindrical shape, and includes a substantially cylindrical hole-communicating connector. The overall size of the two-axis hinge device can be reduced since an electrical connecting member, such as a harness or a flexible board, for connecting electrical components disposed in a first housing and a second housing to each other can be disposed so as to extend through the hole in the second-rotation-axis defining unit and the hole in the hole-communicating connector. The present invention also relates to a mobile terminal apparatus including the two-axis hinge device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2007-281239 (see pages 5 and 6 and FIG. 1) discloses a compact foldable mobile terminal in which the resistance to twisting and bending of a flexible printed circuit (FPC) board is increased. This foldable mobile terminal includes a two-axis hinge mechanism in which a first hinge shaft and a second hinge shaft are connected to each other with a connecting member such that the first and second hinge shafts are perpendicular to each other.
The two-axis hinge mechanism includes an FPC holding structure for holding an FPC including a short section and a long section. The short section is disposed parallel to the second hinge shaft, and the long section is inclined with respect to the short section and is wound around the second hinge shaft. The short section of the FPC is held on the connecting member by a holding member formed of an elastic body that is partially cut in an area near a base end of the wound portion of the long section of the FPC.
In the two-axis hinge mechanism of the above-described foldable mobile terminal, the FPC is held by the holding member formed of the elastic body that is partially cut in an area near the base end of the wound portion. Therefore, the distance between a base end of the FPC at which the FPC is held and the base end of the wound portion of the FPC can be increased without increasing the length of the short section of the FPC. Accordingly, the load applied at the base end of the FPC when the FPC is twisted can be reduced and the resistance to twisting of the FPC can be increased.
In addition, since the holding member is formed of the elastic body, when a load is applied to the FPC, the holding member contracts and thereby suppresses the FPC from being suddenly deformed. In other words, the bending radius at which the FPC is twisted is increased. Thus, the resistance can be increased. In addition, since the short section of the FPC is twisted, the load applied to the long section of the FPC due to the winding of the long section can be reduced. Thus, the load applied to the long section due to the winding thereof can be reduced without increasing the winding radius.